<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
   <title>打星星</title>
</head>
<body>
<link rel="stylesheet" href="demo.css">
<button id="kaishi">开始</button>
<button id="zanting">暂停</button>
<div>
    <span></span>
</div>
<script src="demo.js"></script>
</body>
</html>